Field of the Invention
The technical field of the present invention is that of storage units for electrical energy. More particularly, the present invention concerns an electronic connect/disconnect device for a high voltage electrochemical storage battery designed to be charged and discharged asymmetrically. By high voltage, we mean a voltage greater than or equal to 250 volts.
An electrochemical cell is a power generation device in which chemical energy is converted into electrical energy. The chemical energy originates through electrochemically active compounds deposited on at least one side of electrodes arranged in the storage cell. Electrical energy is produced by electrochemical reactions during discharge of the storage cell. Electrodes, arranged in a container, are electrically connected to current output terminals to provide electrical continuity between the electrodes and an electrical power consuming circuit or load with which the battery is associated.
To increase power output, it is known to associate sealed secondary cells together to form a battery. The battery then has one or more parallel branches of secondary cells connected in series.
Description of Background Art
In the prior art, to protect the output a high-voltage battery from excessive currents and for detecting short-circuit currents, two bidirectional static switches connected back to back in series are often used. This solution is appropriate for low voltage batteries, for example up to 48V, for powers of several tens of kW. However, in the prior art, it was not possible to ensure overlap between charging and discharging for applications with a high output voltage and with high currents.
For this, the use of switches that are bidirectional in terms of voltage arranged in parallel is more suitable for high voltage and high current battery applications for powers of several tens of kW. However, this type of device does not make it possible to obtain rapid and precise measurement and/or control of surge or inrush and short-circuit currents in a high-voltage battery.
There is known for example from DE 10 2013 222462 a device in which two high voltage switches, comprising diodes in series, are arranged in parallel, but this does not allow asymmetric use, with fault currents that can be very high in the discharge direction and with low currents in the charging direction.
To solve this problem, in the above patent application, an external limitation branch is added including a resistor, but this increases the size and cost of the device.
Devices such as those disclosed in US 2007/210758 or US 2015/263559, in which the charging and discharging circuits are arranged in series are known, but these do not make it possible to optimize the charging branch with respect to the discharge branch.
There is therefore a real need for an electronic device capable of quickly and precisely measuring and controlling surge or inrush and short-circuit currents in a high voltage battery taking into account its mode of operation.